This application is not related to any pending United States or international patent application.
This application is not referenced in any Microfiche Appendix.
This invention relates to methods and apparatus for fabricating metal containers and particularly for fabricating relatively large metal containers formed of flat sheets of metal.
In manufacturing metal containers such as those for use for commercial waste disposal, the convention method uses press-breaks that result in multiple handling of large partially formed sheets of steel. The presently used method is cumbersome in that it requires multiple handlings of relatively large steel plates. To form the dimensions of containers made in this conventional manner, substantial effort is required on the part of several workers working with two large formed sections that are brought together to form the four walls of a typical rectangular steel box. As a result of the size and shape of the open end rectangle thus produced often the dimensions are not exactly matched and the squareness of the resulting container is difficult to achieve.
For background information relating to the general subject matter of this invention reference may be had to the following previously issued United States patents:
This invention covers a method of manufacturing a container formed of five rectangular metal panels. The five panels include a bottom panel, opposed side panels and opposed end panels.
The first step in forming a container of such five panels is to form spaced apart notches leaving interposition tab portions in edges of the five metal panels. Typically, such alternate notches and tabs are formed on all four of the edges of the bottom panel and on at least three of the edges of the end and side panels. Depending upon the ultimate configuration of the container, such notches and tabs may or may not be formed on upper edges of the end and side panels.
The bottom panel is supported horizontally. The two side panels and two end panels are then vertically supported around the periphery of the bottom panel with the tab portions along the adjacent edges being aligned with mating notches. The assembly then results in four vertical and four horizontal panel intersections where the tab portions are meshed with notches in adjacent panels. The assembled panels are then welded to each other. Specifically, the bottom edges of the two side and two end panels are welded to the four peripheral edges of the bottom panel. Opposed vertical side edges of the side and end panels are welded to adjacent panel vertical edges.
In a preferred method of manufacturing containers each formed of five rectangular metal panels, the vertical side and end panels are assembled around a bottom panel in an assembly location, after the spaced apart notches and interspersed tab portions are formed on the edges of the five panels. After the assembly is completed, it is moved along a track to a weld station where the bottom edges of the side and end panels are welded to the bottom panel and the adjacent vertical edges of the side panels and end panels are welded to each other. The vertical panels are held in place utilizing hydraulically actuated clamps at each of the four vertical panel intersections to thereby insure accurate positioning of the panels with respect to each other and with respect to the bottom panel and to insure increased consistency of right angle relationships between the panels.
The welding step is preferably carried out using a robotic welder operating within the vertically supported side and end panels.
A better understanding of the invention will be obtained by reference to the following detailed description of the invention taken in conjunction with the attached drawings.
FIG. 1 is a lay-out plan of a metal container manufacturing system that employs the methods of this invention.
FIG. 2 is a fragmentary exploded view of three flat metal sheets that have notches and tabs formed on their peripheral edges.
FIG. 3 shows the three flat metal sheets of FIG. 2 assembled together to form one corner of a metal container with the tabs and notches interlocked.
FIG. 4 is an isometric view showing the construction of a metal container. FIG. 4 shows the container with a horizontal bottom sheet (not seen) with opposed end panels and opposed side panels positioned with respect to each other.
FIG. 5 is an isometric view taken from an opposite side of the perspective of FIG. 3 and shows hydraulically positioned angular clamps at opposed corners of the sidewalls. The positioning clamps are used to hold the sidewalls in place on the bottom panel during welding operation.
FIG. 6 is an enlarged isometric view of a lower corner of a metal container showing a hydraulically actuated positioning clamp used to retain an end panel and a side panel in position on a bottom panel during the assembly of a container.